This package adds new fields of "name" type to the standard
entry types of BibLaTeX. For example: maineditor, for a
@collection, means the editor of @mvcollection, and not the
editor of the @collection. bookineditor, for a @bookinbook,
means the editor of the entry, and not, as the standard editor
field, the editor of the volume in which the entry is
contained.
